Salmo ischchan, Kessler, 1877

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 639

Salmo ischchan

Common name. Sevan trout.

Diagnosis. Distinguished from other species of Salmo in Caspian basin by: ○ flank with small or middle-sized black spots, smaller than 10 mm in diameter in individuals larger than 300 mm SL / ○ flank silvery, without orange spots / ○ parr marks present up to about 100 mm SL. Size up to 760 mm SL and 15 kg.

Distribution. Armenia: Lake Sevan.

Habitat. Lacustrine, spawned in lake, in gravel, close to springs and in mouth of inflowing streams.

Biology. Spawned in autumn–early winter. Fed mainly on benthic gammarid crustaceans.

Conservation status. Extinct.

Remarks. The name S. danilewskii has been used for small individuals feeding on gammarids and plankton. Salmo danilewskii is a synonym, and these fish were most likely small individuals of S. ischchan.

Further reading. Levin et al. 2022 (Sevan trout).

The end of Lake Sevan’s trout diversity. The abundance of Sevan trout declined significantly in the 20 th century due to human impacts. A critical 18.5 m drop in the lake water level and a reduction of>42 % in the lake’s volume for hydropower purposes resulted in the shrinkage of spawning sites for trout spawning in the lake. Furthermore, temperature and oxygen regimes, as well as the hydrochemical composition of the water in the lake, also changed significantly after the drop in the lake level. These alterations, coupled with overfishing, poaching, and the impact of non-native Coregonus , have led to the decline of Sevan trout populations, which eventually resulted in the extinction of the two lacustrine forms known as S. ischchan and S. danilewskii in the 1980s. Only two species survived, namely S. aestivalis and S. gegarkuni . However, they are rarely found in the lake and are largely kept alive by farming and stocking. Further reading. Aghasyan & Kalashyan 2010; Gabrielyan 2010 (conservation); Levin et al. 2022 (Sevan trout).

Salmo kottelati, Alakır stream, Türkiye; male, ~ 105 mm SL.